Aircraft: UAV - UNPILOTED AERIAL VEHICLE
Phase of flight: Cruise
Anomaly: Aircraft Equipment Problem Less Severe

The [ ] Police Department requested assistance in locating a missing autistic teenager that had been missing for about three hours. It was reported the missing child with diminished intelligence was barefoot and without a coat. Sources felt the male teenager would likely find a spot and hide. The outside air temperature at the time of the search was about 55 degrees Fahrenheit. The subject was last seen around the neighborhood pool complex; which was located a couple of blocks away from the child's residence. The neighborhood was a tight network of townhomes. I decided the better landing zone (LZ) would be in the pool complex parking lot or on the wider open street next to it. After relocating and establishing the LZ; I readied the aircraft for flight. The top and bottoms strobes were turned on; blades attached; and the aircraft was powered up. There were no error messages except for an SD card error on the visual camera. Since it was night; there was going to be little need for the visual camera. I determined to launch with that error. The thermal camera was set for White Hot ISO with isotherms turned on for people search. The thermal and visual cameras operated normally. I went to approximately 240 feet AGL and made a 360 degree turn with the thermal camera at 0 degrees to see if any obstructions could be identified. None were identified; so I selected that as my search altitude. I began a loose grid search with [ ] looking over my shoulder at the screen to assist in spotting possible targets. The normal targets alerted; including sewer covers; electric transformers; street lights; and many heat pumps located behind homes. [ ] went to examine the back of one row of townhomes that had a different target. He reported back it was more HVAC units generating heat signatures. When the first battery was down to 20% flight time; I began to head back to the LZ to change batteries. [ ] changed the batteries to another fully charged TB55 set. I launched again and went to an altitude of 240 feet AGL and began a grid search across the area. There were times towards the edge of the grid search where I lost sight of the aircraft; but I continued the search because this was a missing disadvantaged child. Since there were no people spotted below; I felt the risk to people on the ground was minimal. I accepted the risk for the flight and continued. Approximately six minutes into the second flight; the aircraft showed about 18 minutes of flight time remaining. I observed I had lost control of the thermal camera gimbal and could not move it from a 55 degree down angle. I was at the furthermost most point on one of the grid arms and hovering over a possible target I was going to have visually examined. I felt that the target may have been a street light with the head of the light under or in the trees but it may have also been a person sitting under a tree. Without warning the aircraft gave me a battery voltage error and a statement it was landing immediately. I was unable to keep the aircraft in the air; and the most I could do was guide the aircraft to a Final Termination Point (FTP) and get the aircraft to the ground without injuring anyone. Without the ability to move the thermal camera; I was left with few options. I could see what might have been an open field in front of me with some trees nearby. There was what appeared to be one of the primary streets into the neighborhood in front of me; but I had no idea of any traffic approaching on that road or trees below me. I turned to the left and spotted one of the townhome parking lots that was a dead end. I attempted to keep the aircraft in the air to look for any other FTPs; but the aircraft continued descending; and I received a message that it only had seconds of flight time remaining. I decided to put the aircraft down in the townhome parking area and began directionally controlling the aircraft during an uncontrolled descent to what I felt was a safe landing area considering I had no camera gimbal control. Police Department officers on the scene said the aircraft passed close over the roof of one row of townhomes and landed in the center of the dead-end street. DJI Matrice 210 pilot reported landing the UA with only minutes to spare due to a mechanical issue and loss of power.